1. Field of the Invention
The present invention is related to a liquid crystal display (LCD) and a gate discharge control circuit thereof, and more particularly to a liquid crystal display (LCD) and a gate discharge control circuit thereof that are capable of discharging residual charge of pixels during shutting down the LCD to avoid flickering when turning on the LCD.
2. Description of the Prior Art
In general, the LCD uses driving circuits to generate gray-level signals of the pixels of the display panel of the LCD, and the driving circuits comprise a gate driving circuit and a source driving circuit. The gate driving circuit is coupled to a plurality of gate lines (i.e. scan lines) to output gate pulse signals to the pixels, and the source driving circuit is coupled to a plurality of data lines (i.e. source lines) to transmit data signals to the pixels. An intersection of each gate line and each data line is coupled to two ends of an active component (e.g. agate and a source of a thin-film transistor) of a corresponding pixel.
Nowadays, a low temperature poly-silicon (LTPS) LCD of the prior art has a plurality of serially-connected stages of shift registers that are removed from the gate driving chip of the LCD and formed on a glass substrate, so as to form a gate driver on array (GOA) of the LCD. When the shift registers of the gate driving circuit sequentially output the gate pulse signals to sequentially turn on the thin-film transistors coupled to the scan lines, the source driving circuit outputs the corresponding data signals simultaneously to charge the pixel capacitors (including a storage capacitor and a liquid crystal capacitor) of the pixels coupled to the data lines to the desired voltage levels, such that the pixels may display corresponding gray-levels. Due to the operations of charging the pixels, charge may be accumulated in the pixel capacitors of the prior art LCD after a long operating time, such that the pixel capacitors may maintain at an undesired voltage level. In such condition, if the LCD is turned off suddenly, an instant image displayed on the LCD may remain parts of a previous image. Accordingly, the operations of discharges the residual charge of pixels of the LCD of the prior art merely depend on the leakage currents of the thin-film transistors of the pixels, such that the blur of the LCD may represent longer while shutting down the LCD.
To avoid the blur of the LCD, the voltage level of each gate line shall be pulled up immediately while shutting down the LCD, such that the charge accumulated in the pixel capacitors may be released speedily. In the prior art, a power IC is used to provide an XON signal while the LCD is shut down so as to pull up the voltage level of each gate line immediately while shutting down the LCD, such that the charge of the pixel capacitors of the pixels may be released. However, if the cycle of turning on/off the LCD is repeated several times in a short time, residual charge of the pixel capacitors may be accumulated, such that flickering of the display panel of the LCD may be not avoided.